Oil wells (also referred to as “wellbores” or “boreholes”) are drilled with a drill string that includes a tubular member having a drilling assembly (also referred to as the “bottomhole assembly” or “BHA”). The BHA typically includes devices and sensors that provide information relating to a variety of parameters relating to the drilling operations (“drilling parameters”), behavior of the BHA (“BHA parameters”) and parameters relating to the formation surrounding the wellbore (“formation parameters”). A drill bit is attached to the bottom end of the BHA. The drill bit is rotated by rotating the drill string and/or by a drilling motor (also referred to as a “mud motor”) in the BHA in order to disintegrate the rock formation to drill the wellbore.
A large number of wellbores are drilled along contoured trajectories. For example, a single wellbore may include one or more vertical sections, deviated sections and horizontal sections through differing types of rock formations. When drilling progresses from a soft formation, such as sand, to a hard formation, such as shale, or vice versa, the rate of penetration (“ROP”) of the drill changes and can cause (decreases or increases) excessive fluctuations or vibration (lateral or torsional) in the drill bit. The ROP is typically controlled by controlling the weight-on-bit (“WOB”) and rotational speed (revolutions per minute or “RPM”) of the drill bit so as to control drill bit fluctuations. The WOB is controlled by controlling the hook load at the surface and the RPM is controlled by controlling the drill string rotation at the surface and/or by controlling the drilling motor speed in the BHA. Controlling the drill bit fluctuations and ROP by such methods requires the drilling system or operator to take actions at the surface. The impact of such surface actions on the drill bit fluctuations is not substantially immediate. It occurs a time period later, depending upon the wellbore depth.
Therefore, there is a need to provide an improved drill bit and a system for using the same for controlling drill bit fluctuations and ROP of the drill bit during drilling of a wellbore.